gistfile1.txt

result:

before
a
before
b
after


expected:

before
a
after
before
b
after

test.ml

type t = A | B

let f typ =
        print_endline "before";
        match typ with
        | A -> print_endline "a"
        | B -> print_endline "b";
        print_endline "after"

let () = f A
let () = f B